Vertical multi-station local forming method for automobile half axle and pre-forging die

Abstract

The invention discloses a vertical multi-station local forming method for an automobile half axle and a pre-forging die. The method comprises the following steps: blanking to obtain a blank; the blank is subjected to straightening treatment, and a bar is obtained; local induction heating is conducted on the end, needing to be formed, of the flange part on the bar; pre-forging is conducted; a vertical forming process is adopted, a plurality of forming stations are arranged, the bars are sequentially subjected to multiple times of upsetting and gathering on the forming stations through a press machine, and blanks with cylindrical-table-shaped end structures are formed after the bars are subjected to upsetting and gathering on the forming stations; performing finish forging on the blank to form the flange part; forming the spline part; according to the forging method, multiple forming stations are arranged, a conventional press machine is adopted for carrying out multiple times of upsetting and gathering on the cylindrical bar to forge the flange part, and compared with other machining modes in the prior art, the equipment investment is small, the material utilization rate is high, the machining cost is low, and the machining efficiency is high.

Description

Technical Field

[0001] The invention relates to the field of automobile parts production, and in particular to a vertical multi-station local forming method and a pre-forging die for an automobile half-axle. Background Art

[0002] The half shaft of a commercial vehicle is the drive shaft in the drive axle unit that connects the wheels and the driven gear of the main reducer to achieve wheel drive and differential turning. It usually has an external spline at one end and a flange at the other end. The flange is connected to the wheel hub by bolts, and the external spline engages with the internal spline of the driven gear of the main reducer.

[0003] The flange at the end of the existing half-shaft structure is a complex rotating body, making overall half-shaft processing quite complex. Existing flange forming methods typically involve multi-station forming on a flat forging machine and subsequent swing rolling. Blanking is typically achieved by heating and gathering materials on an electric forging machine or by wedge rolling. Flat forging machines and electric forging machines are expensive and costly. Wedge rolling requires a large amount of excess material to be reserved at both ends before processing to facilitate subsequent machining, resulting in low material utilization and processing efficiency.

[0004] In view of the above-mentioned defects, the inventors of the present invention finally obtained the present invention after a long period of research and practice. Summary of the Invention

[0005] To address the above technical deficiencies, the present invention adopts a technical solution that provides a vertical multi-station partial forming method for an automobile half-shaft, which is used to process an automobile half-shaft, wherein the two ends of the automobile half-shaft are respectively provided with a spline portion and a flange portion. The vertical multi-station partial forming method for an automobile half-shaft comprises the following steps:

[0006] S1, cutting to obtain blanks;

[0007] S2, straightening the blank to obtain a bar;

[0008] S3, performing local induction heating on the end portion of the bar material where the flange portion is to be formed;

[0009] S4, pre-forging; using a vertical forming process, setting up several forming stations, the bar material is sequentially subjected to multiple upsetting and gathering at each forming station through a press, and a blank having a cylindrical cone-shaped end structure is formed after the upsetting and gathering at each forming station;

[0010] S5, final forging to form the flange portion;

[0011] S6, forming the spline portion.

[0012] Preferably, in step S3, the heating length range of the bar material is determined according to the material volume of the flange portion, the heating length is set to 350 mm to 500 mm, and the heating temperature is set to 1200°C ± 30°C.

[0013] Preferably, in step S4, the forming stations include a primary upsetting station, an intermediate upsetting station and a final upsetting station, the primary upsetting station upsetting and gathering the bar material to form a first station blank, the intermediate upsetting station upsetting and gathering the first station blank to form a second station blank, and the final upsetting station upsetting and gathering the second station blank to form a third station blank, the first station blank, the second station blank and the third station blank are all arranged as cylindrical cone structures, and the heights of the first station blank, the second station blank and the third station blank decrease successively, and the maximum cross-sectional diameters of the first station blank, the second station blank and the third station blank increase successively.

[0014] Preferably, the height reduction of the bar when deformed toward the first station blank is not greater than 2.5 times the diameter of the bar; the maximum cross-sectional diameter of the first station blank is not greater than 1.5 times the diameter of the bar.

[0015] Preferably, in step S4, the extrusion speed of the press is set to be above 50 mm / s.

[0016] Preferably, in step S4, the extrusion speed of the press is set to 70 mm / s to 120 mm / s.

[0017] Preferably, a pre-forging die is used to implement the step S4 in the vertical multi-station local forming method of the automobile half-axle, the pre-forging die includes an upper die part and a lower die part, the upper die part includes a first upper module, a second upper module and a third upper module, the first upper module, the second upper module and the third upper module are all fixedly set on the upper template, the upper template is slidably set on the sliding assembly, the first upper module, the second upper module and the third upper module are arranged in a straight line along the sliding direction of the upper module, the first upper module is set corresponding to the primary upsetting station, the second upper module is set corresponding to the intermediate upsetting station, and the third upper module is set corresponding to the final upsetting station, the lower die part includes a lower die, and the lower die is fixedly set on the workbench through the lower template, the first upper module, the second upper module and the third upper module are all provided with a forming cavity, and the lower die is provided with a placement cavity, each of the forming cavities can be respectively set corresponding to the placement cavity, and the upper end of the bar placed in the placement cavity is set corresponding to the forming cavity.

[0018] Preferably, the sliding assembly includes a slide, a slide and a fixed plate, the upper template is fixedly set on the slide, the slide is slidably connected to the slide, the slide can slide linearly along the slide, the slide is fixedly set on the fixed plate, and the fixed plate is connected to the pressing block of the press.

[0019] Preferably, the forming cavities are all configured as cylindrical cone-shaped structures, and the diameter of the upper end of the forming cavity is smaller than the diameter of the lower end of the forming cavity.

[0020] Preferably, the lower end surfaces of the first upper module, the second upper module and the third upper module are at the same height.

[0021] Compared with the prior art, the beneficial effect of the present invention is that: by setting multiple forming stations, the present invention uses a conventional press to perform multiple upsetting and gathering of cylindrical bars to forge the flange part. Compared with other processing methods in the prior art, the equipment investment is small, the material utilization rate is high, the processing cost is low and the processing efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A structural view of the automobile half shaft;

[0023] Figure 2 This is a schematic diagram of the structure of the bar after completing step S3;

[0024] Figure 3 This is a schematic structural diagram of the blank after completing step S4;

[0025] Figure 4 A schematic diagram of the structure of the workpiece with the flange portion after completing step S4;

[0026] Figure 5 This is the processing structure view before pre-forging;

[0027] Figure 6 A view of the processing structure at the primary upsetting station;

[0028] Figure 7 A view of the processing structure at the intermediate upsetting station;

[0029] Figure 8 It is a view of the processing structure at the final upsetting station.

[0030] The numbers in the figure represent:

[0031] 1-automobile half shaft; 2-upper die part; 3-lower die part; 11-spline part; 12-flange part; 21-first upper module; 22-second upper module; 23-third upper module; 24-upper template; 25-sliding assembly; 31-lower die; 32-lower template; 33-workbench; 34-barrel; 35-elevator; 211-forming cavity; 251-slide plate; 252-slide table; 253-fixed plate; 311-placing cavity; 312-lower die barrel; 313-first lower module; 314-second lower module; 315-forming protrusion; 321-blanking hole; 341-discharging hole; 342-elevating hole; 351-limiting block. DETAILED DESCRIPTION

[0032] The above and other technical features and advantages of the present invention are described in more detail below with reference to the accompanying drawings.

[0033] Example 1

[0034] The vertical multi-station partial forming method of an automobile half shaft of the present invention is used to process an automobile half shaft, wherein the two ends of the automobile half shaft 1 are respectively provided with a spline portion 11 and a flange portion 12. Figures 1 to 4 As shown, Figure 1 A structural view of the automobile half shaft; Figure 2 This is a schematic diagram of the structure of the bar after completing step S3; Figure 3 This is a schematic structural diagram of the blank after completing step S4; Figure 4 It is a structural schematic diagram of the workpiece with the flange portion after completing step S4.

[0035] The vertical multi-station local forming method for an automobile half-axle comprises the following steps:

[0036] S1, blanking: cutting the long rod to a fixed length by sawing or shearing to obtain a blank;

[0037] S2, straightening: straightening the blank cut to length to obtain a straight bar;

[0038] S3, local induction heating; using a medium frequency furnace to perform local induction heating on the end of the straightened bar material where the flange portion 12 needs to be formed;

[0039] S4, pre-forging; using a vertical forming process, setting up several forming stations, the bar material is sequentially subjected to multiple upsetting and gathering at each forming station through a press, and a cylindrical table-shaped blank is formed after the upsetting and gathering at each forming station;

[0040] S5, final forging the flange portion 12; forging the flange portion 12 by a vertical forming process on an electric screw press on the pre-forged blank;

[0041] S6, forming the spline portion 11.

[0042] Preferably, in step S3, the heating length range of the bar is determined according to the material volume of the flange portion 12, and the heating length is calculated by dividing the volume of the flange portion 12 by the cross-sectional area of ​​the bar, plus a certain length of processing allowance. The heating length is generally set to 350mm~500mm, and the heating temperature is set to 1200℃±30℃.

[0043] Preferably, in step S4, at least three forming stations are provided. Specifically, the forming stations include a primary upsetting station, an intermediate upsetting station and a final upsetting station. The primary upsetting station upsets and gathers the bar material to form a first-station blank. The intermediate upsetting station upsets and gathers the first-station blank to form a second-station blank. The final upsetting station upsets and gathers the second-station blank to form a third-station blank. The first-station blank, the second-station blank and the third-station blank are all arranged as cylindrical cone structures, and the heights of the first-station blank, the second-station blank and the third-station blank decrease successively, and the maximum cross-sectional diameters of the first-station blank, the second-station blank and the third-station blank increase successively.

[0044] In step S4, the size parameters of the first station blank, the second station blank and the third station blank are designed based on the material volume analysis of the flange part 12, so as to ensure the filling effect of the blank in the mold after each upsetting and gathering, avoid processing defects, and at the same time ensure that the blank that meets the subsequent processing requirements is obtained after multiple upsetting and gathering processes.

[0045] At the primary upsetting station, the cylindrical end of the bar is processed to form a cylindrical cone-shaped blank for the first station. Therefore, the most critical factor in the blank design is the size design of the blank for the first station. Specifically, the height reduction of the bar when deforming toward the first station is no more than 2.5 times the diameter of the bar; the maximum cross-sectional diameter of the first station is no more than 1.5 times the diameter of the bar, which can ensure that it does not lose stability during forging. The height reduction of the bar when deforming toward the first station is the length change between the bar and the first station blank after the upsetting at the primary upsetting station. In order to minimize the number of forming stations, the deformation of the portion forming the flange portion 12 at the primary upsetting station should be maximized.

[0046] In step S4, the extrusion speed of the press is set to be above 50 mm / s, preferably 70 mm / s to 120 mm / s, to ensure that the temperature of the billet after pre-forging is above the final forging temperature. When the extrusion speed is lower than 20 mm / s, there is a risk of folding defects on the large end face of the billet, i.e., the end of the large cross-sectional diameter of the cylindrical cone.

[0047] In step S6, this step can be selectively implemented based on the structural requirements of different axle shafts. For example, if the maximum cross-sectional diameter of the spline portion 11 of the overall structure of the automotive axle shaft 1 is larger than the shaft diameter of the automotive axle shaft 1, this step is necessary. Specifically, the end portion where the spline portion 11 is to be formed is locally heated, and then the material is upset and aggregated within the die to form the spline portion 11 of the specific structure. Alternatively, conventional processing methods can be used to produce the desired spline structure of the spline portion 11 based on actual conditions.

[0048] The present invention sets multiple forming stations and uses a conventional press to perform multiple upsetting and gathering of cylindrical bars to forge the flange portion 12. Compared with other processing methods in the prior art, the present invention requires less equipment investment, has a high material utilization rate, low processing cost and high processing efficiency.

[0049] Example 2

[0050] The pre-forging die of the present invention includes an upper die portion 2 and a lower die portion 3, wherein the upper die portion 2 includes a first upper module 21, a second upper module 22 and a third upper module 23, wherein the first upper module 21, the second upper module 22 and the third upper module 23 are all fixedly arranged on an upper template 24, and the upper template 24 is slidably arranged on a sliding assembly 25, and the first upper module 21, the second upper module 22 and the third upper module 23 are arranged in a straight line along the sliding direction of the upper module, the first upper module 21 corresponds to the primary upsetting station, and the second upper die Block 22 is set corresponding to the intermediate top upsetting station, and the third upper module 23 is set corresponding to the final top upsetting station. The lower mold part 3 includes a lower mold 31, and the lower mold 31 is fixed on the workbench 33 through the lower template 32. The first upper module 21, the second upper module 22 and the third upper module 23 are all provided with a forming cavity 211, and the lower mold 31 is provided with a placement cavity 311. Each of the forming cavities 211 can be respectively set corresponding to the placement cavity 311, and the upper end of the bar placed in the placement cavity 311 is set corresponding to the forming cavity 211.

[0051] like Figures 5 to 8 As shown, Figure 5 This is the processing structure view before pre-forging; Figure 6 A view of the processing structure at the primary upsetting station; Figure 7 A view of the processing structure at the intermediate upsetting station; Figure 8 It is a view of the processing structure at the final upsetting station.

[0052] The sliding assembly 25 includes a slide plate 251, a slide 252 and a fixed plate 253. The upper template 24 is fixedly arranged on the slide plate 251. The slide plate 251 is slidably connected to the slide 252. The slide plate 251 can slide linearly along the slide 252. The slide 252 is fixedly arranged on the fixed plate 253. The fixed plate 253 is connected to the pressure block of the press. The press is used to apply pressure to realize the downward pressing operation of the upper mold part 2 to the lower mold part 3, thereby realizing the top upsetting operation of the forming cavity 211 on the upper end of the bar material.

[0053] The upper mold part 2 is provided with a plurality of workstations. Under the control and drive of the hydraulic or electric control system of the press, the first upper mold block 21, the second upper mold block 22 and the third upper mold block 23 are moved forward and backward by a preset distance so that the upper mold of each workstation is aligned with the lower mold 31.

[0054] The present invention sets different upper modules and realizes the transition of different forming stations through the linear sliding of the upper modules, so that the bar material set in the lower die part 3 can be repeatedly upset and gathered to complete the forging of the flange part 12 through a conventional press. Compared with other processing methods in the prior art, the equipment investment is small, the material utilization rate is high, the processing cost is low and the processing efficiency is high.

[0055] Generally, the forming cavity 211 is configured as a cylindrical cone structure, with the upper diameter of the forming cavity 211 being smaller than the lower diameter, thereby enabling the top upsetting of the upper end of the bar stock. The lower end of the forming cavity 211 transitions with the lower end surfaces of the first upper die block 21, the second upper die block 22, and the third upper die block 23 in a circular arc.

[0056] Preferably, the depth of the forming cavity 211 of the first upper module 21, the second upper module 22 and the third upper module 23 decreases successively, and the maximum cross-sectional diameter of the forming cavity 211 of the first upper module 21, the second upper module 22 and the third upper module 23 increases successively, so that the pre-forged billet of the desired shape and size is gradually formed through the first upper module 21, the second upper module 22 and the third upper module 23 in sequence.

[0057] Generally, the lower end surfaces of the first upper die block 21, the second upper die block 22, and the third upper die block 23 are at the same height, thereby ensuring that when the first upper die block 21, the second upper die block 22, and the third upper die block 23 are closing the lower die 31, the downward stroke of the upper die portion 2 driven by the press is consistent, which is more convenient for continuous processing. The first upper die block 21, the second upper die block 22, and the third upper die block 23 are all provided with an upper die seat, and the upper die seat is designed as an assembly with the corresponding upper die. The upper die seat of each station is made into a stepped height. By adjusting the height of the upper die of each station, the goal of ensuring the height consistency of the upper die seat and the upper die assembly is achieved.

[0058] Example 3

[0059] The lower mold 31 includes a lower mold barrel 312, a first lower module 313 and a second lower module 314. The first lower module 313 and the second lower module 314 are arranged in sequence from top to bottom in the lower mold barrel 312. The first lower module 313 and the second lower module 314 are fixedly arranged on the lower template 32 through the lower mold barrel 312. The placement cavity 311 includes a forming section and a fixing section. The forming section is arranged on the upper part of the first lower module 313, and the fixing section is arranged on the second lower module 314. A forming protrusion 315 is also provided on the upper surface of the first lower module 313. The shape structure of the forming section and the forming protrusion 315 corresponds to the end structure of the automobile half-axle 1, so as to form the connecting part of the flange part 12 and the automobile half-axle 1.

[0060] Generally, the forming section is set to a cylindrical cone shape, so that the diameter of the automobile half-axle 1 gradually increases when the end extends toward the flange part 12 to improve the connection strength between the flange part 12 and the automobile half-axle 1, and the forming protrusion 315 is set at the upper end edge of the placement cavity 311. The forming protrusion 315 is set to a circular ring structure with a circular arc cross-section, thereby forming an annular groove structure of the flange part 12, which is used to reduce the contact between the flange and the mounting surface to facilitate debugging during installation.

[0061] The fixing section is configured to be cylindrical, and the cross-sectional diameter of the fixing section is consistent with the cross-sectional diameter of the bar material, thereby facilitating the fixing of the bar material in the lower die 31 .

[0062] The lower template 32 is provided with a blanking hole 321 corresponding to the placement cavity 311 . The diameter of the blanking hole 321 is larger than the cross-sectional diameter of the fixed section, so that waste oxide scale generated during processing can be more easily leaked downward from the blanking hole 321 .

[0063] The lower die portion 3 also includes a barrel 34, which is fixedly mounted on the workbench 33. A discharge hole 341 is vertically disposed within the barrel 34. The discharge hole 341 corresponds to the placement cavity 311 and has a diameter greater than the cross-sectional diameter of the fixed section. The provision of the barrel 34 facilitates the placement of long-sized bars within the lower die portion 3. The fixed section ensures the stability of the bars within the lower die portion 3. The size of the discharge hole 341 further facilitates the placement of long-sized bars within the lower die portion 3. The barrel 34 for placing the bars within the lower die portion 3 is provided on the lower die portion 3 to withstand the forming forces during upsetting.

[0064] Preferably, a top hole 342 is provided at the bottom of the discharge hole 341, and a top rod 35 is provided in the top hole 342. The top rod 35 can move vertically. The rod in the discharge hole 341 can be pushed out by the top operation of the top rod 35, so as to facilitate the removal of the processed rod.

[0065] Generally, a limiting block 351 is provided at the upper end of the push rod 35, and a limiting cavity is provided at the upper end of the ejection hole 342. The diameter of the limiting cavity is smaller than the diameter of the discharge hole 341. The diameter of the limiting block 351 is larger than the diameter of the ejection hole 342 and smaller than the diameter of the limiting cavity. When the rod is normally placed in the discharge hole 341, the limiting block 351 is set in the limiting cavity to avoid the influence of the limiting block 351 on the bottom of the rod, thereby ensuring that the rod is placed stably in the discharge hole 341.

[0066] The present invention provides a mold frame structure for vertical multi-station top upsetting of materials. The key is that the upper mold of each station can be moved to a specified position according to a pre-set program. At the same time, the barrel 34 is pre-buried in the workbench 33, and the space below the press workbench 33 is used to realize vertical forging of 1.5-meter-long rods.

[0067] Example 4

[0068] The main operating steps of the pre-forging die of the present invention are:

[0069] Mold moving and preparation for loading and unloading: the upper mold part 2 is moved up to the loading and unloading position to prepare for robot loading;

[0070] Cleaning oxide scale: Use compressed air to clean the oxide scale on the mold surface and inside the barrel 34 to keep the mold free of foreign matter;

[0071] Spray lubricant: Use a spray gun to evenly spray lubrication on the upper and lower mold cavities;

[0072] Local induction heating: Use medium frequency furnace to perform local induction heating on the part that needs to be formed. The heating length range is determined by the material volume of 12 parts of the flange part, generally 350mm~500mm, and the heating temperature is 1200℃±30℃;

[0073] Loading: The robot grabs the locally heated bar material and places it in the lower die part 3, and the bottom of the barrel 34 receives the bar material;

[0074] Primary upsetting die transfer forming: the upper die part 2 is pushed to the primary upsetting station, so that the first upper die block 21 is aligned with the lower die part 3, and the upper die part 2 moves downward to upset the bar material in the first upper die block 21. After the forming is completed, the upper die part 2 moves upward to a preset position;

[0075] Intermediate upsetting die transfer forming: the upper die part 2 is pushed to the intermediate upsetting station, so that the second upper die block 22 is aligned with the lower die part 3, and the upper die part 2 moves downward to upset the bar material in the second upper die block 22. After the forming is completed, the upper die part 2 moves upward to the preset position;

[0076] Final upsetting die transfer forming: the upper die part 2 is pushed to the final upsetting station, so that the third upper die block 23 is aligned with the lower die part 3, and the upper die part 2 moves downward to upset the bar material in the third upper die block 23. After the forming is completed, the upper die part 2 moves upward to a preset position;

[0077] Unloading: The upper die part 2 moves to the loading and unloading position, and the ejector rod 35 pushes the workpiece to the unloading position, where it is grabbed and removed by the robot.

[0078] The above description is merely a preferred embodiment of the present invention and is intended to be illustrative rather than restrictive of the present invention. Those skilled in the art will appreciate that many changes, modifications, and even equivalents may be made to the present invention within the spirit and scope of the claims, all of which fall within the scope of protection of the present invention.

Claims

1. A vertical multi-station partial forming method for an automobile half shaft, used for processing an automobile half shaft, wherein the two ends of the automobile half shaft are respectively provided with a spline portion and a flange portion, characterized in that: Including steps: S1, cutting to obtain blanks; S2, straightening the blank to obtain a bar; S3, performing local induction heating on the end portion of the bar material where the flange portion is to be formed; S4, pre-forging; using a vertical forming process, setting up several forming stations, the bar material is sequentially subjected to multiple upsetting and gathering at each forming station through a press, and a blank having a cylindrical cone-shaped end structure is formed after the upsetting and gathering at each forming station; S5, performing final forging on the blank to form the flange portion; S6, forming the spline portion.

2. The vertical multi-station partial forming method for an automobile half-axle according to claim 1, characterized in that: In step S3, the heating length range of the bar material is determined according to the material volume of the flange portion, the heating length is set to 350 mm to 500 mm, and the heating temperature is set to 1200°C ± 30°C.

3. The vertical multi-station partial forming method for an automobile half-axle according to claim 1, characterized in that: In step S4, the forming stations include a primary upsetting station, an intermediate upsetting station and a final upsetting station. The primary upsetting station upsets and aggregates the bar material to form a first-station blank. The intermediate upsetting station upsets and aggregates the first-station blank to form a second-station blank. The final upsetting station upsets and aggregates the second-station blank to form a third-station blank. The first-station blank, the second-station blank and the third-station blank are all arranged as cylindrical cone structures, and the heights of the first-station blank, the second-station blank and the third-station blank decrease successively, and the maximum cross-sectional diameters of the first-station blank, the second-station blank and the third-station blank increase successively.

4. The vertical multi-station partial forming method for an automobile half-axle according to claim 3, characterized in that: The height reduction of the bar when deforming toward the first station blank is no more than 2.5 times the diameter of the bar; the maximum cross-sectional diameter of the first station blank is no more than 1.5 times the diameter of the bar.

5. The vertical multi-station partial forming method for an automobile half-axle according to claim 4, characterized in that: In the step S4, the extrusion speed of the press is set to be above 50 mm / s.

6. The vertical multi-station partial forming method for an automobile half-axle according to claim 4, characterized in that: In the step S4, the extrusion speed of the press is set to 70 mm / s to 120 mm / s.

7. A pre-forging die, characterized in that: Used to implement step S4 in the vertical multi-station local forming method of an automobile half-axle as described in any one of claims 3 to 6, the pre-forging die includes an upper die portion and a lower die portion, the upper die portion includes a first upper module, a second upper module and a third upper module, the first upper module, the second upper module and the third upper module are all fixedly set on the upper template, the upper template is slidably set on the sliding assembly, the first upper module, the second upper module and the third upper module are arranged in a straight line along the sliding direction of the upper module, the first upper module is set corresponding to the primary upsetting station, the second upper module is set corresponding to the intermediate upsetting station, and the third upper module is set corresponding to the final upsetting station, the lower die portion includes a lower die, and the lower die is fixedly set on the workbench through the lower template, the first upper module, the second upper module and the third upper module are all provided with a forming cavity, and the lower die is provided with a placement cavity, each of the forming cavities can be set respectively corresponding to the placement cavity, and the upper end of the bar placed in the placement cavity is set corresponding to the forming cavity.

8. The pre-forging die according to claim 7, wherein: The sliding assembly includes a slide plate, a slide and a fixed plate. The upper template is fixedly set on the slide plate. The slide plate is slidably connected to the slide plate. The slide plate can slide linearly along the slide plate. The slide plate is fixedly set on the fixed plate. The fixed plate is connected to the pressing block of the press.

9. The pre-forging die according to claim 7, wherein: The forming cavities are all configured as cylindrical table structures, and the diameter of the upper end of the forming cavity is smaller than the diameter of the lower end of the forming cavity.

10. The pre-forging die according to claim 7, wherein: The lower end surfaces of the first upper module, the second upper module and the third upper module are at the same height.

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